Online Water Quality Tester Parameter Range PH:0.00-14.00PH ORP:-2000mv~+2000mv EC:0-19000us/cm,0-199.0ms/cm CF:0-1999.0CF TDS:0~19990ppm,0~199.0ppt SALT:0~199.9pptï¼?0%~20% S.G:0.990~1.400 Temp: 0~50�°C( 32 �°F~122�°F) Resolution PH:0.01PH ORP:1mV EC:1us/cm( 1999)